// Copyright 2024 RisingWave Labs
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::sync::LazyLock;

use risingwave_common::catalog::PG_CATALOG_SCHEMA_NAME;
use risingwave_common::types::DataType;

use crate::catalog::system_catalog::BuiltinView;

/// The catalog `pg_description` stores description.
/// Ref: [`https://www.postgresql.org/docs/current/catalog-pg-description.html`]
pub static PG_DESCRIPTION: LazyLock<BuiltinView> = LazyLock::new(|| BuiltinView {
    name: "pg_description",
    schema: PG_CATALOG_SCHEMA_NAME,
    columns: &[
        (DataType::Int32, "objoid"),
        (DataType::Int32, "classoid"),
        (DataType::Int32, "objsubid"),
        (DataType::Varchar, "description"),
    ],
    // objsubid = 0     => _row_id (hidden column)
    // objsubid is NULL => table self
    sql: "SELECT objoid, \
                 classoid, \
                 CASE \
                     WHEN objsubid = 0 THEN -1 \
                     WHEN objsubid IS NULL THEN 0 \
                     ELSE objsubid \
                 END AS objsubid, \
                 description FROM rw_catalog.rw_description \
          WHERE description IS NOT NULL;"
        .into(),
});
